Question #f8fe8

1 Answer
Jun 15, 2017

#0#

Explanation:

Since we're differentiating with respect to #x#, we want to track how the function changes as #x# changes.

The function in question is #cos^2(a+y)#, which doesn't depend on #x# at all. So, as #x# changes, #cos^2(a+y)# doesn't change at all.

So, with respect to #x#, the function #cos^2(a+y)# is constant, and

#d/dxcos^2(a+y)=0#